Train-control system



Nov. 19, 1929. c. s. BUSHNELL 1,736,735

' TRAIN CONTROL SYSTEM Filed March 12, 1927 g AcK.

INVE O/RHI Patented Nov. 19, 192

UNITED STATES PATENT OFFICE CHARLES S. BUSHNELL, OF ROCHESTER, NEE/YORK; ASSIGNOR' TO GENERAL RAILWAY SIGNAL COMPANY, OF ROCHESTER, NEW YORK TRAIN-CONTROL. SYSTEM Application filed March 12,-1927. Serial No. 174,861.

This invention relates in general toa train control system,- and has more particular reference to an intermittent inductive train control system 01 the alternating current type. including acknowledging andreset means.

In train control systems of the type re ferred to, it is usual to have spaced track way inductors controlled in accordance with the trafiic conditions and arranged to inductively influence a normally energized, alternating current, car-carried receiver, to cause such receiver to produce a train restricting influence, such as a brake application, or the like, unless prevented by the proper operation of an acknowledging device. If the train restricting influence be exerted it is then generally necessary to manually operate a reset device to restore the various parts to normal. In such systems the car-carried device usually comprises a main relay, with its energizing circuit tuned to the frequency or the current employed when its armature is picked up, so that after being re-energized, I

it its armature assume detracted position, the energizing circuit is thereby detuned, and removal of the trackway influence does not permit picking up of the armature ofsuch relay, it being necessary, in some independent manner, to restore the armature to attracted position.

lVith the above and other-considerations in mind, it is proposed, in accordance with this invention, to provide acknowledging and reset means for respectively preventing, for a temporary period, the dropaway, of the main relay armature, upon de-energization of such relay, and for restoring the dropped away armature to attracted position.

More specifically stated, it is proposed in accordance with this invention to provide acknowledging and reset means including separate coils carried by the core of the main relay and operative, when energized, to move the armature of the main relay to, and to retain it in, attracted position. These separate coils can be energized by means of an acknowledging contactor through a circuit including front contacts of the main relay, and also by means of a specially positioned a railway track comprising track rails 1,

divided intov signalling sections, in a usual manner, by insulating joints 2, each block being provided with a wayside signal 3 ot the semaphore type, and an inductor 4 positioned alongside the trackway adjacent the entrance end of each block. As indicated bydotted lines, the inductors are controlled by the signals to place them in active condition under-caution and danger conditions of the particular block in question, and to,

place them in inactive condition under clear conditions of such block, the various control means tor the signals and the inductors not having been shown or descrlbed as they are deemed non-essential to a complete under? standing of the present invention.

Carried on the car, represented diagrammatically by wheels and axles 5, is a receiver having, a core 6 carrying primary and secondary coils, P and S, the primary coils be ing included in a circuit comprising a source or alternating current 7, preferably of a frequency higher than commercial, such for eX- ample as 360 cycles per second, and a condenser 8, so chosen as to tune the circuit in;

question to the frequency of the current employed. The secondary coils S are included in a similarly tuned circuit including a con denser 9 and coils lOcarried on a core 11 of,

a main relay MR, the core 11, and the cor-e 6 and inductor 4, all being of magneticma terial and preferably laminated to cut down eddy current losses.

The main relay MR includes a pivotedarmature 12, biased to its retracted position;

by a spring 13, and having contact fingers 14 and 15 electrically insulated from the body of the armature by insulating joints 16.

The organization includes a device, EPV, arranged to control a car brake or a train restricting means of some character, and as shown in the drawing, is contemplated as being an electro-pneumatic device, normalsly ener ized, and which, on de-energization,

ZJ initiates the train restricting influence.

A reset contactor Res is provided and includes a manually operable rod 17, arranged to operate contact fingers18 and 19.

An acknowledging device, designated as A070 includes a spring biased depressible rod 20, arranged to operate contact lingers 21 and 22, the finger 21 moving with the rod, and the finger 22 being arranged, by means of a dash pot 23 and spring means 2a, 2 1 to slowly open after operation of the rod 20, in a well known manner, the time constant in the particular case in question being prel erably about 15 seconds, whereby contact finger 22 does not break contact until about 15 seconds after operation of the acknowledging device.

Included on the core 11 of the main relay MR, as part of this system, are two reset and acknowledging coils 25, for a purpose to be later described.

In order to simplify the wiring diagram and the description, symbols B and C have been employed to indicate opposite poles of a source or sources of direct current energy such, for example, as a storage battery, which, unc or certain circumstances, could obviously likewise indicate the opposite instantaneous poles of an alternating current source or sources of electrical energy.

The various parts have been shown in the drawings in their normal conditions and positions, that is,the conditions and positions existing with the train proceeding in clear territory.

The primary and secondary coils, P and S, on the receiver are inductively related to each other so that coils 10 of main relay MR are normally energized by current induced in secondary coils S, to thereby hold main relay armature 12 in picked up position.

The inductors and receiver are so positioned that the receiver passes over each inductor,

in inductive relation thereto, through a small air gap, and when the inductor is 1nactive,

no appreciable effect is produced on the reis in active condition, corresponding to danger or caution traffic conditions, the flux distribution in the receiver core6 is so modified as to reduce the amountof current flowing through the secondary circuit including coils 10, to zero, or substantially so, whereby to de-energize main relay MR.

Assume, for the purpose of explanation, that the train is proceeding from a clear to a caution block, and that the engineman performs no act of acknowledgement when passing over the active inductor at the entrance to such block. In these circumstances, relay MR becomes (lo-energized, causing its armature 12 to drop away and thereby break the normal EI V energizing circuit through con tact finger 15 and front contacts of relay MB, to thereby cause an automatic brake application.

T he dropping away of armature 12 of main relay MR detunes the secondary circuit so that resumption of How of induced current in such circuit is insuilicient to restore arm-a ture 12 and thereby re-energize EPV to release the brakes and allow the train to proceed, even though the secondary circuit were not taken through 'I'ront contacts and contact finger 14. of the relay, making it a stick device which, when-once (ls-energized so remains until otherwise restored. In this connection, it should be noted that detuning a circuit fed with high frequency alternating current, is substantially equivalent to opening a circuit fed with direct current.

It is necessary, for the train to proceed, to operate the resetdevice Res which is positioned so as to be operable only when the train is at a full stop, accomplished, for example, by positioning it'to be accessible only from the ground. On depressing the reset iod 17 and energized circuit for the reset coils 25 is completed which can be traced f om a source of energy B, contact finger 18 and back contact of R68, coils 25, to a source C, to thus attract the armature 12 and restore it to normal attracted position, whereupon the secondary circuit including the coils 10 becomes again complete, and also retuned, and

the armature is retained by the normal flow of induced current through the secondary cir cuit even though the reset lever be restored to normal. In this connection it will be seen that it is necessary to'restore the reset lever to normal, since w ien in its operated position, its contact finger 19 and front contact break the normal energizing circuit for EPV.

Under the conditions assumed, namely, that the train is traveling from clear to a caution block, it the engineer is alert and depresses the acknowled ing rod 20 a short time prior to passing theactive inductor l, an acknowledging energiz ng circuit 18 completed tor the acknowledging 00115 25 which can be traced from a source G, the two coils 25 in series, contact linger 21 and back con tact of A070, contact finger 22 and front contact of A070, and contact finger 15 and front contacts of relay MB, to a source B. This acknowledging energizing circuit retains the armature 12 in attracted position despite the de-energization of the relay coils 10 and thus prevents de-energization of EPV and a consequent automatic brake application.

It should be noted that if the acknowledging contactor be tied down, or held down for too long a period, the slow opening contact finger 22 will open after a short time, so that, on encountering the next active inductor, deenergization of the main relay coils 10 will cause an automatic brake application, since the acknowledging energizing circuit for acknowledging coils 25 will have been broken at contact finger 22 and front contact of A070.

From the above it will be seen that in a system of the character in question, an acknowledging and reset means has been provided which are properly protected against misuse, and will perform their desired functions in a most satisfactory manner.

The above rather specific description of one form of the invention, is shown solely by way of example, and is not intended, in any manner whatsoever, in a limiting sense. Obviously, the invention can assume many different physical forms, and is susceptible of numerous modifications, and all such forms and modifications are intended to be included by this application, as come within the scope of the appended claims.

Having described my invention, I now claim 1. In a train control system, a car-carried main relay having a normally energized circuit controlled in accordance with traffic conditions ahead, a brake applying device having an energizing circuit including a front contact of said relay and initiated when deenergized, a coil arranged when energized to place, and to maintain, the armature of the main relay in attracted position, means for only temporarily energizing the coil, and

means for energizing the coil for an indefinite porarily energizing the coil through a circuit including a front contact of the main relay, and means for energizing the coil for an indefinite. time while simultaneously breaking the energizing circuit for the brake applying device.

3. In a train control system, a car-carried main relay having a normally energized circnit controlled in accordance with traffic conditions ahead, a brake applying. device having an energizing circuit including a front contact of said relay and initiated when deenergized, a coil arranged when energized to place, and to maintain, the armature of the main relay in attracted position, acknowledging means, not affecting the energizing circuit of the brake applying device, for only temporarily energizing the coil, and means for energizing the coil for an indefinite time while simultaneously breaking the energizing circuit for the brake applying device.

4. In a train control system, a car-carried main relay having a normally energized tuned circuit controlled in accordance with traflic'conditions ahead, a brake applying device having an energizing circuit including a front contact of said relay and initiated when de-energized, a coil on the core of the main relay for placing and maintaining the armature of the main relay in attracted position, means for only temporarily energizing the coil, and means for energizing the coil for an indefinite time while simulta .neously breaking the energizing circuit for the brake applying device.

5. In a train'controlsystem, a car-carried main relay having a normally energized tuned alternating current circuit controlled in accordance with traffic conditions ahead; a brake applying device having an energizing circuit including a front contact of said relay and initiated when de-energized, a coil arranged when energized to place and main tain the armature of the main relay in attracted position, means for temporarily energizing the coil, and means for energizing the coil for an indefinite time while simultaneously breaking the'energizing circuit for the brake applying device.

6. In a train control system, a car-carried main relay having a normally energized circuit controlled in accordance with traffic conditions ahead, a, brake applying device having an energizing circuit including a front.

contact of said relay and initiated when deenergized, a coil on the core of the main relay for attracting the armature of the main relay to attracted position, acknowledging means for only temporarily energizing thecoil through a circuit including a front contact of the main relay, and means for energizing the coil for an indefinite time while simultaneously breaking the energizing circuit for the brake applying device.

7. In a train control system, a car-carried main relay having a normally energized tuned stick circuit controlled in accordance with traflic conditions ahead, a brake applying device having an energizing circuit ineluding a front contact of said relay and initiated when ole-energized, a coil on the core of the main relay for attracting the armature of the main relay to attracted position, acknowledging means, the operation of wvhich does not affect the energizing circuit of the brake applying device, for only temporarily energizing the coil, and means for energizing the coil While simultaneously V 5 breaking the energizing circuit for the brake applying device.

8. In a train control system, a car-carried main relay having a normally energized tuned alternating current circuit controlled in accordance with traffic conditions ahead,

a brake applying device having an energizing circuit including a front contact of said relay and initiated when de-energized, a coil on the core of the main relay for attracting 1 the armature of the main relay to attracted position, means for only temporarily energizing the coil, and means for energizing the coil while simultaneously breaking the energizing circuit for the brake applying device.

9. In a train control system, a main relay having a tuned energizing circuit controlled in accordance with trafiic conditions ahead, a brake applying device having an energizing circuit including a front contact of the main relay and initiated when de-energized, a coil on the core of the main relay, a manually controlled acknowledging energizing circuit for the coil including a front contact of the relay and a slow opening contact finger, and a manually controlled reset energizing circuit for the coil.

10. In a train control system, a main relay having a stick circuit controlled in accordance with traffic conditions ahead, a brake applying device having an energizing circuit including a front contact of the main relay and initiated when deenergized, a coil on the core of the main relay, a direct current acknowledging energizing circuit for the coil,

including a front contact of the main relay and a slow opening contact finger and independent of the energizing circuit for the brake applying device, and a manuallycontrolled direct current energizing reset circuit for the coil.

In testimony whereof I affix my signature CHARLES S. BUSHNELL. 

